Boiler-furnace.



No. 784,880. PATENTED MAR. 14, 1905;

s. F. PIERCE.

BOILER FURNACE. APPLICATION FILED JUNE 17,1904.

4 SHEETS SHEBT 1.

PATENTED MAR. 14, 1905.

4 SHEETS-SHEET 2.

PATENTED MAR. 14, 1905.

S. F. PIERCE.

BOILER FURNACE.

APPLICATION FILED JUNE 17.1904.

4 SHEETS-SHEET 4.

L I I UNITED STATES Patented March 14, 1 905.

PATENT OFFICE,

BOILER-FURNACE.

SPECIFICATION forming part of Letters Patent No. 784,880, dated March 14:, 1905.

Application filed June 1'7, 1904. Serial No. 212,940.

To all whom it may concern:

Be it known that I, SIMEON F. PIERCE, a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota. have invented certain new and useful Improvements in Boiler-Furnaces, of which the following is a specification.

My invention relates to improvements in boiler-furnaces of the class wherein part or all of the fuel is first coked before being fed to the main grate; and its-object is to provide improved means for leading the smoke and gases generated in the cokingchan'1ber to the main grate-bars, for introducing heated air to the fire-box, and for supporting, strengthening, and preserving the inner wall of the coking-chamber.

To this end my invention consists in the features of construction, combination, and arrangement of parts hereinafter described and claimed.

In the accompanyingd rawings, forming part of this specification, Figure 1 is a view, partly in front elevation and partly in section, on line w of Fig. 2 of a furnace embodying my improvements. Fig. 2 is a vertical section on lines r of Fig. 1. Fig. 3 is a horizontal section on line y g of Fig. 1. Fig. i is a view, partly in front elevation and partly in section, on line w '10 of Fig. 6, showing a modified arrangement of air-inlet pipes. Fig. 5 is a vertical section on line a" a" of Fig. 4, and Fig. 6 is a horizontal section on line ;I/ 1/ .of Fig. 4.

1n the drawings, A represents the masonry side walls, B the front wall, and C the bridgewall, of a furnace in which is seated a boiler D. At the bottom of' the structure is an ashpit 2', above which are the main grate-bars 3 and fire-box 4. In the front wall are the doors 5 and 6 of the main ash-pit and ire-box, respectively, and the doors 7 and 8 of the cokingchamber and its ash-pit, respectively.

On each side of the fire-box and along the side wall of the furnace is a coking-chamber E, extending, preferably, from the front wall of the furnace to the bridge-wall. The side and front walls A and B of the furnace thus constitute the outer side and front walls, respectively, of the coking-chamber, and when the coking chamber extends back to the bridge-wall, as shown in the drawings, the bridge-wall will constitute the rear wall of the coking-chamber. Atthe bottom of the cokingchamber is an endless-chain grate F and below it is an ash-pit 9, having its floor raised above the floor of the furnace to allow room beneath it for the passage 10, hereinafter described. The inner side wall of the cokingchamberthat is, the wall dividing the cokingchamber and its ash-pit from the main lire-box and ash-pit of the furnace comprises a lower upright portion 11 and an arched upper portion 12, extending over the top of the cokingchamber to the side wall of the furnace, which supports the upper end thereof. The wall of the coking-chamber is formed just above the level of the main grate 3 with a longitudinal opening 13, through which the coked fuel passes or is carried out of the coking-chamber onto the main grate.

In order to accomplish the complete discharge of the coke from the coking-chamber to the main grate, as well as to provide a convenient and easily-operated means for regulating the discharge, 1 have provided and endless-chain grate F, composed of pivoted links 14:, passing over interspaced drums 15, square in section, keyed to shafts 16, journaled in suitable bearings,such as the bearings 17 at the rear of the bridge-wall and 18 in the front wall of the furnace. These drums may be operated by means of a crank 1.9,rotatably supported upon a "pin 20 on thefront wall of the furnace, through the medium of intermeshing gears 21 upon thecrank'and 22 upon the end of one of the shafts 16. In order to operate the grate easily and slowly, the gear upon the drum-shaft is made considerably larger than the gear upon the crank. in order that the grate may present a substantially horizontal surface as well near the side walls of the coking-chamber as midway between those walls, the outer wall and the inner wall may be cut away or recessed at 23 and 24, respectively, as shown in the drawings.

If the smoke and gases generated in the coking-chamber were led to the main grate directly or through highly-heated passages, they would reach the grate in so heated a condition as soon to destroy it, particularly if they were discharged into the ash-pitbelow it. it is therefore important that the passages should be so situated and of such length as to allow the gases to cool during their passage therethrough, and it is alsoimportantthat the passages should be constructed and arranged in such way that their walls shall not be destroyed by the heat of the furnace. To accomplish these results, I have provided a passage 25, inset deeply within the outer side wall A of the furnace and extending from the top of the cokirig-chamber down to the bottom of the furnace. This passage communicates with the upper part of the coking-chamber by means of a branch passage 26 in the side wall A and with the ash-pit below the main grate by means of a passage 10, extending from the lower end of the passage 25 underneath the ash-pit of the coking-chamber to the main ash-pit. These passages are preferably of a width from front to back nearly as great as the depth of the coking-chamber.

,In order to supply heated air to the main lire-box to consume the products of combustion, as well as to cool the inner wall of the eoking-chamber, and thus protect it from destruction under the intense heat on both sides of it, I lead th 1 air through the interior of the inner side wall of the coking-chamber by means of air-ductsin the wall comn'mnieating separately with the outside air and discharging into the lire-box at predetermined selected points. In order not only not to weaken the side wall, but positively to strengthen and support it, as well as to secure other structural and operating advantages, I make these d nets of metal pipe having support at one or both ends in the walls of the furnace. This may be done in various ways. ,In the form shown in Figs. 4t, 5, and 6 the pipes 27 are carried horizontally at different levels through the front wall B of the furnace and the inner side wall of the coking-chamber, each pi pe having a separate inlet-opening 28 to the outside air and either discharging into the lire-box through a nozzle 29 in the side wall or extending entirely through the side wall into the bridge-wall and formed therein with a return portion 30, discharging into the lire-box through a nozzle 31. I prefer, however, to arrange the pipes as shown in Figs. 1, 2, and 3, where pipes 32, having each a separate inlet-opening 33, are carried side by side through the side wall A of the furnace and downwardly through the interior of the upper or arched portion 12 of the inner side wall of the coking-chamber. Some of the pipes may extend only part way down the inner side wall, discharging from the side wall into the lire-box through nozzles 34. Others may be turned at an angle into and through the bridge wall, discharging therefrom through nozzles 35, and yet others may lead down to a transverse connnunicating-1, ipc 36 in the side wall 12, supported in the front and bridge walls and discharging into the fire-box from the bridge-wall through a return portion 3'7 therein and nozzle 38. The transverse main pipe 36 lirnil y supported at its ends in the front and bridge walls will afford a strong support for the lower ends of those of the downwardly-extending auxiliary pipes 32 which are secured to and communicate with it, and the connected main and auxiliary pipes supported in the front, side, and bridge walls will make a strong supporting-frame for the inner side wall of the coking-chamber. In order, further, to protect and support the upper arched portion 12 of the inner side wall and to utilize the heat generated in the coking-chamber,- I also prefer to provide pipes 39 extending through the side wall A of the furnace and down along the under or inner side of the arched portion 12 of the inner side wall to the opening 13 therein and then turning at a sharp angle through the opening and under the side wall portion 12, discharging into the fire-box through nozzles 40. The pipes thus form an additional support for the wall portion 12, not only at the bottom, but all the way up to the side wall A of the furnace. l have found in practice that the cooler air flowing through the pipes will save them from destruction by the external heat about them, thus making it possible to use metal pipes in the manner described. By having the pipes lead separately from the outside air a flow of air through all of the pipes is assured, as well as the discharge of air at each of the selected points, and the amount of entering air and its place of discharge can be regulated and controlled In use the coal is supplied to the cokingchamber through the doors '7 and fire is applied at the bottom, a fire being at the same time started upon the main grate 3. As the coal in the coking-chamber becomes coked the smoke and gaseous products of combustion pass into and down the passage 25 in the side wall and the communicating passage 10 to the ash-pit beneath the main grate 3, whence they pass up through the grate and the fuel thereon and are themselves consumed. Being led down below the main grate, the smoke and gases will meet and mix with the currents of air below the grate and will be very completel y consumed as they pass up through the lire. lXlDtllG same time the gases generated by the fire upon the main grate are consumed by the air entering the fire-box through the pipes in and along the walls of the cokingchamber, the air having become heated during its passage through and along the side wall of the coking-chamber to a temperature high enough greatly to promote combustion and not cool off the gases in the fire-box.

\Vhen the coal in the coking-chamber becomes coked at the bottom, the chain grate is driven by means of the crank 19 or any other suitable means to carry the coked products toward and through the opening 13 in the side wall of the coking-chamber. As the grate turns about the forward drum the coke will drop from the chain grate onto the main grate 3 of the furnace, and thus a constant supply of coke may be fed to the fire. The supplying of the coke is facilitated by having the chain grate positioned so that its upper surface will stand at a higher level than the main grate 3, as shown in Fig. l of the drawings.

It is obvious that various modifications may be made in the details of the construction without departing from the principle of the invention, the scope of which is defined in the claims.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a furnace of the class described the combination, with the walls and fire-box thereof, of a coking-chamber arranged at the side of the fire-box and having an inner side wall dividing it therefrom, pipes supported at one end in one of the walls of the furnace and extending through the interior of the inner side wall of the coking-chamber, each pipe leading separately from the outside air and discharging into the fire-box at a predetermined point, and a passage within one of the walls of the furnace and along the bottom thereof leading from the coking-chamber to the ashpit below the main grate.

2. In a furnace of the class described, the combination, with the walls and fire-box thereof, of a coking-chamber arranged at the side of the fire-box and having an inner side wall dividing it from the fire-box, and pipes sup ported at one end in one of the walls of the furnace and extending through the interior of the inner side wall of the coking-chamber,each pipe leading separately from the outside air and discharging into the fire-box at a predetermined point.

3. In a furnace of the class described, the combination, with the side wall and fire-box,

of a coking-chamber arranged at the side of the fire-box and having an inner side wall dividing it therefrom, and pipes passing through the side wall of the furnace and extending downwardly through the interior of the inner side wall of the cokingchamber, said pipes having separate air-inlet openings and discharging into the fire box at predetermined points.

4. In a furnace of the class described the combination, with the front wall, side wall, bridge-wall and fire-box, of a coking-chamber arranged at the side of the fire-box and having an inner side wall dividing it therefrom, a main pipe supported at its ends in the front and bridge walls and passing intermediately through the interior of the inner side wall of the coking-chamber, said pipe extending into the bridge-wall and discharging therefrom into the fire-box, and one or more communicating pipes passing through the side wall of the furnace and extending downwardly through the interior of the inner side wall of the coking-chamber to the main pipe.

5. In a furnace of the class described the combination, with the fire-box, main grate and side wall, of a coking-chamber arranged at the side of the fire-box and havinga dividing-wall extending over the chamber to the sidewall of the furnace, the dividing-wall being formed with an opening above the main grate, and one or more pipes passing through the side wall of the furnace and extending down along the inner side of the dividing-wall and through the opening therein in supporting proximity to the dividing-wall, said pipes being open at both ends, for the purpose set forth.

In testimony whereof I aflix my signature in presence of two witnesses.

SIMEON F. PIERCE.

Witnesses:

ARTHUR P. LoTHRor, EMILY F. OTIS. 

